U.S. patent application number 11/939181 was filed with the patent office on 2008-05-15 for temperature control system for mold and injection molding method using the same.
This patent application is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Woo-Seok CHIN, Ick-Sung CHOE, Chang-Youn HWANG, Shin-Chul KANG, Young-Ki KIM.
Application Number | 20080111280 11/939181 |
Document ID | / |
Family ID | 39125273 |
Filed Date | 2008-05-15 |
United States Patent
Application |
20080111280 |
Kind Code |
A1 |
CHOE; Ick-Sung ; et
al. |
May 15, 2008 |
TEMPERATURE CONTROL SYSTEM FOR MOLD AND INJECTION MOLDING METHOD
USING THE SAME
Abstract
A temperature control system for a mold includes a circulation
pipe provided in the mold, a heating water circulation section to
provide heating water to the circulation pipe to pre-heat the mold,
a cooling water circulation section to provide cooling water to the
circulation pipe to cool the mold, and a compressed air circulation
section to provide compressed air to the circulation pipe to eject
remaining heating water or cooling water within the circulation
pipe. The compressed air circulation section is adapted to supply
the compressed air to the circulation pipe to eject remaining fluid
within the circulation pipe before heating water or cooling water
is provided to the circulation pipe.
Inventors: |
CHOE; Ick-Sung; (Yongin-si,
KR) ; KIM; Young-Ki; (Yongin-si, KR) ; KANG;
Shin-Chul; (Seoul, KR) ; CHIN; Woo-Seok;
(Suwon-si, KR) ; HWANG; Chang-Youn; (Suwon-si,
KR) |
Correspondence
Address: |
H.C. PARK & ASSOCIATES, PLC
8500 LEESBURG PIKE, SUITE 7500
VIENNA
VA
22182
US
|
Assignee: |
SAMSUNG ELECTRONICS CO.,
LTD.
Suwon-si
KR
|
Family ID: |
39125273 |
Appl. No.: |
11/939181 |
Filed: |
November 13, 2007 |
Current U.S.
Class: |
264/328.16 ;
425/144 |
Current CPC
Class: |
B29C 2045/7393 20130101;
B29C 45/7306 20130101; B29C 35/007 20130101 |
Class at
Publication: |
264/328.16 ;
425/144 |
International
Class: |
B29C 45/17 20060101
B29C045/17; B29C 33/02 20060101 B29C033/02 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 14, 2006 |
KR |
10-2006-0112320 |
Claims
1. A temperature control system for a mold, comprising: a
circulation pipe provided in the mold; a heating water circulation
section to provide heating water to the circulation pipe to
pre-heat the mold; a cooling water circulation section to provide
cooling water to the circulation pipe to cool the mold; and a
compressed air circulation section to provide compressed air to the
circulation pipe to eject remaining heating water or cooling water
within the circulation pipe, wherein the compressed-air circulation
section is adapted to supply the compressed air to the circulation
pipe to eject remaining fluid within the circulation pipe before
heating water or cooling water is provided to the circulation
pipe.
2. The temperature control system of claim 1, wherein the heating
water circulation section comprises: a heating water tank; a
heating water circulating pump connected to the heating water tank,
the heating water circulating pump being adapted to provide heating
water of the heating water tank to the circulation pipe; and an air
exhaustion opening disposed the heating water tank, wherein heating
water having circulated through the circulation pipe returns to the
heating water tank.
3. The temperature control system of claim 2, wherein compressed
air, which is supplied to the circulation pipe to eject the
remaining heating water within the circulation pipe, is exhausted
via the air exhaustion opening of the heating water tank after
circulating through the circulation pipe.
4. The temperature control system of claim 3, further comprising a
solenoid valve disposed between the circulation pipe and the
heating circulation pump, wherein the solenoid valve disposed
between the circulation pipe and the heating circulation pump is
adapted to block cooling water or compressed air from flowing
backward to the heating circulation pump.
5. The temperature control system of claim 1, wherein the cooling
water circulation section comprises: a cooling water tank; a
cooling water circulating pump connected to the cooling water tank,
the cooling water circulating pump being adapted to provide cooling
water of the cooling water tank to the circulation pipe; and an air
exhaustion opening disposed in the cooling water tank, wherein
cooling water having circulated through the circulation pipe
returns to the cooling water tank.
6. The temperature control system of claim 5, wherein compressed
air, which is supplied to the circulation pipe to eject the
remaining cooling water within the circulation pipe, is exhausted
via the air exhaustion opening of the cooling water tank after
circulating through the circulation pipe.
7. The temperature control system of claim 6, further comprising a
solenoid valve disposed between the circulation pipe and the
cooling water circulating pump, wherein the solenoid valve disposed
between the circulation pipe and the cooling water circulating pump
is adapted to block heating water or compressed air from flowing
backward to the cooling water circulating pump.
8. The temperature control system of claim 1, further comprising a
solenoid valve disposed at an end of the circulation pipe, wherein
the solenoid valve disposed at the end of the circulation pipe is
adapted to circulate heating water flowing out from the circulation
pipe through the heating water circulation section and to circulate
cooling water flowing out from the circulation pipe through the
cooling water circulation section.
9. The temperature control system of claim 1, further comprising a
solenoid valve disposed between the compressed air circulation
section and the circulation pipe, wherein the solenoid valve
disposed between the compressed air circulation section and the
circulation pipe is adapted to block heating water or cooling water
from flowing backward to the compressed air circulation
section.
10. The temperature control system of claim 1, wherein the
compressed air circulation section comprises a compressor and air
compressed by the compressor is supplied to the circulation
pipe.
11. The temperature control system of claim 1, wherein the heating
water circulation section and the cooling water circulation section
each further comprise a check valve, wherein the check valve of the
heating water circulation section is adapted to block heating water
of the heating water circulation section from flowing backward and
the check valve of the cooling water circulation section is adapted
to block cooling water of the cooling water circulation section
from flowing backward.
12. The temperature control system of claim 1, wherein the
compressed air circulation section supplies compressed air having a
pressure of 3 to 15 kgf/cm.sup.2 to the circulation pipe.
13. The temperature control system of claim 1, wherein the mold is
maintained above a temperature of 50.degree. C. using the heating
water circulation section, and is maintained below a temperature of
95.degree. C. using the cooling water circulation section.
14. An injection molding method, comprising: preheating a mold by
providing heating water from a heating water circulation section to
the mold; injecting melted resin into the preheated mold; ejecting
heating water from the mold containing the melted resin by
providing compressed air from a compressed air circulation section
to the mold; and cooling the mold containing the melted resin by
providing cooling water from a cooling water circulation section to
the mold.
15. The injection molding method of claim 14, wherein preheating
the mold comprises preheating the mold to a temperature above
50.degree. C., and cooling the mold comprises cooling the mold
below a temperature of 95.degree. C.
16. The injection molding method of claim 14, further comprising
ejecting cooling water from the mold by providing compressed air
from the compressed air circulation section to the mold, and then
providing heating water from the heating water circulation section
to the mold.
17. The injection molding method of claim 16, wherein the mold is
maintained above a temperature of 50.degree. C. by ejecting cooling
water from the mold and providing heating water to the mold.
18. The injection molding method of claim 16, wherein the entire
method is repeated.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from and the benefit of
Korean Patent Application No. 10-2006-0112320, filed on Nov. 14,
2006, which is hereby incorporated by reference for all purposes as
if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a mold for injection
molding, and more particularly to a temperature control system for
the mold.
[0004] 2. Discussion of the Background
[0005] Generally, it may be difficult to control the temperature of
a mold in an injection molding process to prepare plastic products.
If the temperature of the mold is too low in the beginning of the
process, it can cause quality defects in the products. After the
temperature of the mold is raised to a suitable temperature, the
mold should be continuously cooled to maintain the suitable
temperature because the temperature rises when melted resin is
injected into the mold. As a result, a molding interval may be
increased, which reduces productivity. Therefore, a temperature
control system, in which the mold has passages formed therein and
the temperature of the mold is controlled within a suitable range
by supplying heating and cooling water into the passages, may be
used.
[0006] However, there are problems in conventional temperature
control systems for molds. Cooling water supplied into the mold
should eject any remaining heating water that is in the mold and at
the same time cool the mold, which reduces the cooling efficiency
of the cooling water. Namely, the cooling water may mix with the
heating water during the ejection of heating water, which may
reduce the cooling efficiency.
[0007] Also, the mold may be supplied with heating water to prevent
supercooling of the mold, but the heating water may have a similar
problem to the cooling water, as discussed above. The heating
water, which is supplied into the mold to reduce cooling rate of
the mold, may mix with remaining cooling water in the mold during
ejection of the cooling water, so the heating efficiency may be
reduced. In addition, reduced efficiencies of cooling and heating
increase the cooling time and heating time of the mold, which may
require additional operations of a cooler and a heater.
Consequently, the manufacturing cost may be increased.
[0008] Moreover, when the cooling water ejects the heating water
while cooling the mold, circulation of the cooling water may not be
performed smoothly due to a repulsion pressure of the heating
water. In the same way, when the heating water ejects the cooling
water while heating the mold, circulation of the heating water may
not be performed smoothly due to repulsion pressure of the cooling
water.
SUMMARY OF THE INVENTION
[0009] The present invention provides a temperature control system
for a mold and an injection molding method using the same, in which
cooling water or heating water in the mold may be easily ejected,
so that preheating and cooling of the mold may be easily
performed.
[0010] The present invention also provides a temperature control
system for a mold and an injection molding method using the same,
which may improve preheating and cooling efficiencies of the mold,
so that the time and cost required for the injection molding
process may be reduced.
[0011] The present invention also provides a temperature control
system for a mold and an injection molding method using the same,
which may reduce the time required for the injection molding
process, so that productivity thereof may be improved.
[0012] Additional features of the invention will be set forth in
the description which follows, and in part will be apparent from
the description, or may be learned by practice of the
invention.
[0013] The present invention discloses a temperature control system
for a mold, which includes a circulation pipe provided in the mold,
a heating water circulation section to provide heating water to the
circulation pipe to pre-heat the mold, a cooling water circulation
section to provide cooling water to the circulation pipe to cool
the mold, and a compressed air circulation section to provide
compressed air to the circulation pipe to eject remaining heating
water or cooling water within the circulation pipe, wherein the
compressed air circulation section is adapted to supply the
compressed air to the circulation pipe to eject remaining fluid
within the circulation pipe before heating water or cooling water
is provided to the circulation pipe.
[0014] The present invention also discloses an injection molding
method including preheating a mold by providing heating water from
a heating water circulation section to the mold, injecting melted
resin into the preheated mold, ejecting heating water from the mold
containing the melted resin by providing compressed air from a
compressed air circulation section to the mold, and cooling the
mold containing the melted resin by providing cooling water from a
cooling water circulation section to the mold.
[0015] It is to be understood that both the foregoing general
description and the following detailed description are exemplary
and explanatory and are intended to provide further explanation of
the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this specification, illustrate embodiments of
the invention, and together with the description serve to explain
the principles of the invention.
[0017] FIG. 1 is a schematic view showing a configuration of a
temperature control system for a mold according to an exemplary
embodiment of the present invention.
[0018] FIG. 2 is a view showing a preheating step of the
temperature control system of FIG. 1.
[0019] FIG. 3 is a view showing a first forming step of the
temperature control system of FIG. 1.
[0020] FIG. 4 is a view showing a second forming step of the
temperature control system of FIG. 1.
[0021] FIG. 5 is a view showing a re-preheating step of the
temperature control system of FIG. 1.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
[0022] The invention is described more fully hereinafter with
reference to the accompanying drawings, in which embodiments of the
invention are shown. This invention may, however, be embodied in
many different forms and should not be construed as limited to the
embodiments set forth herein. Rather, these embodiments are
provided so that this disclosure is thorough, and will fully convey
the scope of the invention to those skilled in the art. Like
reference numerals in the drawings denote like elements.
[0023] As shown in FIG. 1, a temperature control system 100 for a
mold 109 includes a circulation pipe 191 provided in the mold 109,
a heating water circulation section, a cooling water circulation
section, and a compressed air circulation section, in which the
heating water circulation section, the cooling water circulation
section, and the compressed air circulation section are connected
with the circulation pipe 191, respectively. The temperature
control system 100 is adapted to eject remaining cooling water or
heating water within the circulation pipe 191 using compressed air
before providing heating water or cooling water to the circulation
pipe 191.
[0024] The heating water circulation section includes a heating
water tank 111 and a heating water circulating pump 113 to supply
heating water to circulation pipe 191. The heating water tank 111
has an air exhaustion opening 117 disposed therein, and may have a
constant temperature equipment or a heating device (not shown) to
maintain heating water therein at a constant temperature. The
heating water circulating pump 113 is disposed between the heating
water tank 111 and the circulation pipe 191 to supply heating water
of the heating water tank 111 to the circulation pipe 191. When the
heating water circulating pump 113 is working, the circulation pipe
191 is continuously supplied with heating water, wherein heating
water, which has circulated through the mold 109 by passing through
the circulation pipe 191, is returned into the heating water tank
111.
[0025] Here, there is disposed at least one check valve 119 on a
path of the heating water circulation section, which is adapted to
block heating water flowing therethrough from flowing backward. In
this exemplary embodiment, two check valves 119 are respectively
disposed at an outlet of the heating water circulating pump 113 and
at an inlet of the heating water tank 111.
[0026] Between the circulation pipe 191 and the heating water
circulating pump 113, there is disposed at least one first solenoid
valve 115. Each first solenoid valve 115 is adapted to open a path
between the heating water circulating pump 113 and the circulation
pipe 191 to allow heating water to pass when the heating water is
supplied to the mold 109, and to close the path between the heating
water circulating pump 113 and the circulation pipe 191 to prevent
fluid within the circulation pipe 191 from flowing backward to the
heating water circulating pump 113.
[0027] The cooling water circulation section includes a cooling
water tank 121 and a cooling water circulating pump 123, with which
it supplies cooling water to the circulation pipe 191. The cooling
water tank 121 has an air exhaustion opening 127 disposed therein,
and may have a constant temperature equipment or a cooling device
(not shown) to maintain cooling water therein at a constant
temperature. The cooling water circulating pump 123 is disposed
between the cooling water tank 121 and the circulation pipe 191 so
as to supply cooling water of the cooling water tank 121 to the
circulation pipe 191. When the cooling water circulating pump 123
is working, the circulation pipe 191 is continuously supplied with
cooling water, wherein cooling water, which has circulated through
the mold 109 by passing through the circulation pipe 191, is
returned to the cooling water tank 121.
[0028] Here, there is disposed at least one check valve 129 on a
path of the cooling water circulation section, which is adapted to
block cooling water flowing therethrough from flowing backward. In
this exemplary embodiment, two check valves 129 are respectively
disposed at an outlet of the cooling water circulating pump 123 and
at an inlet of the cooling water tank 121.
[0029] Between the circulation pipe 191 and the cooling water
circulating pump 123, there is disposed at least one second
solenoid valve 125. Each second solenoid valve 125 is adapted to
open a path between the cooling water circulating pump 123 and the
circulation pipe 191 to allow cooling water to pass when the
cooling water is supplied to the mold 109, and to close the path
between the cooling water circulating pump 123 and the circulation
pipe 191 to prevent fluid within the circulation pipe 191 from
flowing backward to the cooling water circulating pump 123.
[0030] Consequently, when the circulation pipe 191 is supplied with
cooling water by the cooling water circulating pump 123, the first
solenoid valves 115 close to block the cooling water from flowing
into the heating water circulating pump 113, and when the
circulation pipe 191 is supplied with heating water by the heating
water circulating pump 113, the second solenoid valves 125 close to
block the heating water from flowing into the cooling water
circulating pump 123.
[0031] In the temperature control system 100, the heating water
tank 111 and the cooling water tank 121 are respectively connected
with the circulation pipe 191, so that they receive the heating
water or cooling water flowing out from the circulation pipe 191.
The heating water tank 111 and cooling water tank 121 are connected
with the circulation pipe 191 via at least one third solenoid valve
193. Each third solenoid valve 193 is adapted to selectively
connect one of the heating water tank 111 and the cooling water
tank 121 to the circulation pipe 191. Namely, when the heating
water circulating pump 113 is working, the third solenoid valves
193 connect the heating water tank 111 to the circulation pipe 191,
and when the cooling water circulating pump 123 is working, the
third solenoid valves 193 connect the cooling water tank 121 with
the circulation pipe 191.
[0032] The compressed air circulation section includes a compressor
131 and a fourth solenoid valve 135 and supplies compressed air
having a pressure of 3 to 15 kgf/cm.sup.2 to the circulation pipe
191. Here, the compressed air supplied to circulation pipe 191
flows into one of the heating water tank 111 and the cooling water
tank 121, and is exhausted out of the tank 111 or 121 through the
air exhaustion opening 117 or 127.
[0033] Here, when the heating water circulating pump 113 or the
cooling water circulating pump 123 is working, the fourth solenoid
valve 135 blocks heating water or cooling water from flowing into
the compressor 131.
[0034] Consequently, the first, second, and fourth solenoid valves
115, 125, and 135 block fluid from flowing backward from the
circulation pipe 191 to the heating water circulating pump 113, the
cooling water circulating pump 123, or the compressor 131. In
addition, the third solenoid valves 193 connect the circulation
pipe 191 with the heating water tank 111 or the cooling water tank
121 based on whether remaining fluid within the circulation pipe
191 is heating water or cooling water.
[0035] FIG. 2, FIG. 3, FIG. 4, and FIG. 5 sequentially show an
injection molding process using the mold 109 with the temperature
control system 100 described above. Hereinafter, an injection
molding method using the mold 109 with the temperature control
system 100 is explained with reference to FIG. 2, FIG. 3, FIG. 4,
and FIG. 5.
[0036] FIG. 2 shows a preheating step 100a of the mold 109. The
preheating step 100a is to preheat the mold 109 before the mold 109
is injected with melted resin, so that the melted resin does not
harden while it is injected to the mold 109. Namely, when a
temperature of the mold 109 is too low relative to a temperature of
the melted resin, only a part of the melted resin, which comes into
contact with the mold 109 when injected thereto, is rapidly
solidified. As a result, differences in the temperature and the
solidification rates of a part of the resin that is first
solidified and a remaining part the resin are generated, which may
lower the quality of an injection molding product. Therefore, the
mold 109 is supplied with heating water before injection of the
melted resin so that the mold 109 is preheated to a temperature
ensuring that the resin is not rapidly solidified while it is
injected. In this exemplary embodiment, the mold 109 is preheated
to a temperature above 50.degree. C. and then the melted resin is
injected to the mold 109.
[0037] In the preheating step 100a, each first solenoid valve 115
opens a path between the circulation pipe 191 and the heating water
circulating pump 113, while the second and fourth solenoid valves
125 and 135 close the paths connected therewith, respectively. In
addition, the third solenoid valves 193 open a path between the
circulation pipe 191 and the heating water tank 111 while closing
the path between the circulation pipe 191 and the cooling water
tank 121. Therefore, when the heating water circulating pump 113 is
in operation, the heating water of the heating water tank 111
passes through the circulation pipe 191 and returns to the heating
water tank 111.
[0038] Although not shown, when the mold 109 is sufficiently
preheated, melted resin is injected into the mold 109. When the
injection of the melted resin is finished, then the melted resin
injected into the mold 109 is solidified. A passage, through which
the melted resin is injected into the mold 109, is formed
independently of the heating water circulation section, cooling
water circulation section, and compressed-air circulation section.
The temperature of the mold 109 is rapidly raised when it is
injected with the melted resin, but the temperature of the mold is
prevented from going beyond 95.degree. C. by performing a first
forming step 100b and a second forming step 100c.
[0039] In this exemplary embodiment, the forming steps are divided
into a first forming step 100b and a second forming step 100c. The
forming steps promote the solidification of the melted resin
injected into the mold 109 by lowering the temperature of the mold
109, for example, the temperature of the entire mold 109 may be
uniformly lowered. This is to obtain a uniform characteristic of
the injection molding product by solidifying the whole of the
melted resin injected into the mold 109 at the same time.
[0040] Referring to FIG. 3, the first forming step 100b is a step
of ejecting remaining heating water within the mold 109, and
ultimately within the circulation pipe 191, by injecting compressed
air into the circulation pipe 191. The remaining heating water is
thoroughly ejected prior to the injection of cooling water into the
mold 109, thereby improving the rate and efficiency of cooling of
the mold 109. In first forming step 100b, the first solenoid valves
115 and the second solenoid valves 125 are closed. The fourth
solenoid valve 135 opens the path between the compressor 131 and
circulation pipe 191. Since the first forming step 100b is the step
of ejecting the heating water within the circulation pipe 191, each
third solenoid valve 193 opens a path between the circulation pipe
191 and the heating water tank 111.
[0041] When the mold 109 is injected with melted resin, the mold
109 is naturally cooled since the temperature of the mold 109 is
above room temperature. However, in the exemplary embodiment of the
present invention, the cooling water is supplied to the mold 109
after heating water is within the mold 109, which promotes cooling
of the mold 109 and ultimately cooling of the melted resin injected
into the mold 109.
[0042] As the heating water is ejected by providing compressed air
into the circulation pipe 191 of the mold 109, the cooling of the
mold 109 begins. Thus, the melted resin injected into the mold 109
begins to solidify slowly.
[0043] The second forming step 100c is a step to further promote
the solidification of melted resin injected into the mold 109, in
which cooling water is supplied to the circulation pipe 191.
Referring to FIG. 4, the cooling water circulating pump 123 is in
operation and the second solenoid valves 125 open in the second
forming step 100c. Also, the third solenoid valves 193 connect the
circulation pipe 191 with the cooling water tank 121. Here, the
first solenoid valves 115 and the fourth solenoid valve 135 are
closed.
[0044] The cooling water supplied to the circulation pipe 191 cools
the mold 109, and thus promotes the solidification of the melted
resin injected into the mold. When an injection molding process is
performed again after the injection molding product is released
from the mold in this step where the cooling water is being
supplied into the circulation pipe 191, it may be necessary to
monitor the temperature of the mold 109 to ensure that it does not
go below 50.degree. C.
[0045] If no additional injection molding process is needed, the
molding process is finished by releasing the injection molding
product from the mold 109. After that, if a new injection molding
process is needed, the injection step and the first and second
forming steps 100b and 100c may be repeated after performing a
re-preheating step 100d.
[0046] Referring to FIG. 5, during the re-preheating step 100d, the
preheating step 100a is repeated after ejecting the cooling water
within the circulation pipe 191. This is required when an
additional injection molding product is prepared after having
released the mold product from the mold 109. Here, the ejecting of
the cooling water within the circulation pipe 191 is performed in a
way similar to the first forming step 100b, in which the first and
second solenoid valves 115 and 125 are closed, and the third
solenoid valves 193 connect the circulation pipe 191 with the
cooling water tank 121. When the flow path of fluid described above
is set up, the compressor 131 supplies compressed air into the
circulation pipe 191 to eject the cooling water within the
circulation pipe 191.
[0047] The compressed air, which passes through the circulation
pipe 191 in the first forming step 100b and re-preheating step
100d, is ejected via the air exhaustion opening 117 of the heating
water tank 111 or the air exhaustion opening 127 of the cooling
water tank 121.
[0048] During re-preheating step 100d, the temperature of the mold
109 is maintained above 50.degree. C. by performing the preheating
step 100a after ejecting the cooling water within the circulation
pipe 191. If the temperature of the mold 109 is maintained above
50.degree. C. after ejecting the cooling water within the
circulation pipe 191, the preheating step 100a of the re-preheating
step 100d, i.e. the process for providing the heating water to the
circulation pipe 191, may be omitted.
[0049] When the injection step, the first forming step 100b, and
the second forming step 100c are carried out after the
re-preheating step 100d as described above, an injection molding
product having the same shape may be prepared, and if this is
repeated, products having the same shape may be repeatedly
obtained.
[0050] According to the temperature control system for a mold and
injection molding method using the same of the exemplary
embodiments of the present invention as described above, since the
remaining heating and cooling water within the mold are ejected
using compressed air when the mold is repeatedly preheated and
cooled, fluid may easily flow through the mold in the preheating
and cooling processes. In addition, by preventing the heating water
and the cooling water from mixing with each other using compressed
air, the cooling and heating efficiencies of the mold may be
improved. Consequently, the cooling time and the heating time of
the mold may be reduced, which may improve the productivity
thereof. Also, the improved efficiencies of the cooling and heating
may result in reduced costs, such as a reduced cost of fuel.
[0051] The temperature of the mold according to the exemplary
embodiment of the present invention is limited to the range from
50.degree. C. to 95.degree. C., but it may be variously modified by
those skilled in the art according to conditions, such as the types
of melted resin to be injected into the mold and the design
dimension of injection molding products to be prepared.
[0052] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the invention. Thus,
it is intended that the present invention cover the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *